1. Field of the Invention:
This invention relates generally to the medical field of urology, and more particularly to inflatable balloons for dilation of the prostate uretha, and to methods for the treatment of benign prostatic hyperplasia using the same.
2. Art Background:
Benign prostatic hypertrophy is a common occurrence in older males. One major effect of this disorder is the constriction of the urethra within the prostate resulting in a number of symptoms in a patient, including nocturia, frequency of urination, stanguria and post-void dribbling, as well as varius related emotional and other physical problems. Currently, there are several forms of treatment for this prostate disorder, including drug therapy, hypothermia treatment, surgical treatment such as transurethral prostatectomy (TURP), implantation of prostatic stents and dilation balloon therapy.
The TURP procedure is surgical, subjecting the patient to a number of risks including post-operative bleeding, stricture formation at the urethra or bladder neck, incontinence, post-manipulation pain or bladder spasms, urinary infections, reactive urethral swelling causing urinary obstruction, epididymitis, as well as other standard problems associated with post surgery recovery. Additionally, the surgery requires 1-3 hours of operating room time, approximately a one-week recovery in the hospital and a significant amount of additional recovery time before the patient is fully able to resume normal function.
Another method for prostate treatment involves the injection or application of drugs or other medications into or adjacent the prostate gland by means of a catheter disposed adjacent the gland. This medication is frequently ineffective due to the poor absorption capability of the prostate gland as well as the difficulty in positioning and retaining the catheter with respect to the affected area. Accordingly, several patents, namely U.S. Pat. Nos. 3.977,408; 2,642,874 and 550,238, disclose the use of balloons to retain the catheter in place while medication is applied to the gland, and U.S. Pat. Nos. 2,936,760 and 550,238 also teach the use of balloons to isolate regions of the urethra in order to provide medicine to the localized area.
Dilation balloon catheters are commonly used for the removal of constrictions caused by deposits of plaque in arteries as is taught in U.S. Pat. No. 4,636,195.
There are also now several reports of the use of balloon catheters in treatment of benign prostate hypertrophy. U.S. Pat. No. 4,660,560 issued to Klein, discloses the treatment of obstructive tissue in the prostrate urethra with a balloon catheter wherein the proximal end of the catheter is anchored in the bladder by means of a Foley or fixation balloon and an annular balloon surrounding the catheter is dilated to dilate the prostate urethra. Proper location of the dilation balloon and proper sizing of the dilation balloon are critical in order to prevent having the dilation balloon being disposed in the sphincter thereby causing serious damage to the sphincter and making it impossible to control urine flow thereafter. Proper location of the annular balloon is obtained by first introducing into the urethra a cystoscope and a graduated catheter having length markings along its exterior and measuring the length of the prostate by counting the measurement lines. Once the proper size of the annular balloon is determined, it is inserted into the urethra through a disposable introducing sheath and the sheath is withdrawn to expose the dilating balloon. The position of the balloon is detected using radiological techniques. Alternatively, the position of the dilating may be detected by an endoscope inserted through the sheath adjacent the dilating balloon and its associated catheter to observe its position and ensure that the dilating catheter is entirely within the prostate. Once properly located, the positioning balloon is inflated to retain the catheter in position during the procedure. Thereafter, the dilating balloon is inflated and maintained in its inflated state for at least 10 minutes. The balloons are then deflated and the device removed. A Foley catheter may be inserted to assist in voiding for the first 1 to 2 days after the treatment. Recovery requires only several days. Preliminary studies of this treatment using the foregoing device have been favorable. (Urology Times, "Two-balloon Prostate Dilation Improves Voiding Symptoms" Feb. 1989, P. 1; Surgical Practice News, "Balloon Catheter Procedure Obviates Surgery for Benign Prostatic Hypertrophy Blockage" September 1988)
U.S. Pat. No. 4,932,956 issued to Reddy, et al. discloses a prostate balloon dilator having a fixation balloon disposed on a catheter distal to the dilation balloon. The dilation balloon need not be sized because any excess balloon merely sticks up into the bladder. The distal fixation balloon is disposed in the urethra distal to the sphincter and is localized in that position by palpation of a hardened ring disposed proximal to the fixation balloon. Localization of the balloon is also obtained by means of post-insertion radiology by detecting the radio-opaque markers disposed at critical positions along the balloon or catheter. Success with this method and apparatus in treating benign prostatic hyperplasia has been demonstrated. (Reddy, et al., Contemporary Urology, "Balloon dilation of the prostate: Can it help the patient with BPH?" February/March 1989, p. 44 et seq.)
As is evident from the foregoing patents, a major element of successful dilation of the prostate depends upon the proper placement of the balloon within the prostate combined with immobilization of the dilation balloon so that it does not migrate out of the prostate. It is also of utmost importance that the dilation balloon is not be expanded while it is disposed within the urethral sphincter. To ensure that the dilation balloon is not within the sphincter, the currently preferred method is to provide an cystoscope and visualize the location of the balloon to verify its location. This requires that two objects, namely the dilation catheter and the scope, be placed within the urethra. Both devices can be placed within one large sheath or catheter. However, this procedure is cumbersome and uncomfortable to the patient since such a large sheath or catheter must be placed within the urethra. It should also be noted that additional tubes for irrigation are oftentimes provided through the catheter as well. Accordingly, patients are at least anesthetized locally if not placed under general anesthesia in order to minimize the discomfort to the patient.
In our U.S. patent application Ser. No. 539,865 we disclose a ureteral stent and cystoscope combination for insertion of the stent and observation of the same. The scope in that application is in the form of a fiber optic bundle having an appropriate provision for light and lensing thereof, and preferably having a video camera and monitor responsive to the image formed at the proximal end of the scope for viewing during the scope insertion process. The fiber optic bundle itself is sufficiently small so that the entire scope may be fabricated with the appropriate dimensions and is made sufficiently flexible for movement through the urethra, the bladder and into the ureter.